Machine tools, such as milling machines, lathes, chucking machines, drill presses, automatic spindle machines, grinders, and the like commonly utilize a liquid coolant to cool the workpiece being machined. The coolant is usually directed at the point of contact between the tool and workpiece, and the machine tool coolant system normally consists of a pump being supplied from a sump or reservoir which pressurizes a conduit system for directing coolant flow to the location desired, and the discharged coolant returns to the sump or reservoir.
As the machining operations normally produce chips of various sizes, grit, and the like, the coolant contains various types of foreign matter which is continually recycled through the coolant system, and continued use of the coolant increases the contamination, while the coolant, which is usually a mixture of water and oils, serves as a breeding source for bacteria, all of which contaminates the coolant to the degree where it must be periodically replaced.
While the inclusion of small chips, grit and other foreign matter in the coolant adversely affects the quality of the machining operation, there is increasing concern over the health aspects of bacterial growth within the coolant in that the machine tool operator is exposed to the coolant.
Presently, as machine tool coolant becomes contaminated, either from the inclusion of foreign matter, bacterial growth, or both, the coolant is entirely discarded and replaced, which is expensive, or large stationary coolant processing equipment is used to process and reclaim the coolant. Such processing apparatus is very expensive, and available, for economic reasons, only to large users of machine tool coolant, and complex conduit and coolant handling systems are necessary when using such apparatus. Accordingly, small machine tool operations not having access to permanently installed coolant processing equipment must periodically discard the coolant and replace the same with fresh liquid.
It is an object of the invention to provide a coolant processing system for machine tools wherein the apparatus is relatively inexpensive, portable and may be readily utilized with a wide variety of machine tools to reclaim and renew the coolant.
A further object of the invention is to provide a coolant processing system utilizing portable apparatus including a plurality of pumps and filters wherein the coolant is removed from the machine tool coolant reservoir, pumped through a plurality of filters in a sequential manner to remove foreign matter and bacteria, and returned to the machine tool coolant system.
A further object of the invention is to provide an economical coolant processing and reclaiming system utilizing easily serviceable and maintained components and employing two pumps, one pump drawing contaminated coolant from the machine tool reservoir and pumping the coolant through a coarse filter into a reservoir mounted upon a portable frame, and the second pump removing the coarse filtered coolant from the frame-mounted reservoir and pumping the coolant through a fine filter and returning the twice-filtered coolant to the machine tool coolant system.
An additional object of the invention is to provide a coolant processing system employing two electric pump and filtering units connected in series wherein an accumulator reservoir receiving the discharge of one pump contains float-operated swtiches for controlling the pumps and controlling the pump and filter cycles.
In the practice of the invention a wheel-mounted frame supports first and second centrifugal pumps, and an accumulator reservoir is also mounted upon the frame. The first pump includes a suction conduit for drawing from the machine tool coolant system and the first pump discharges into a coarse filter located within the accumulator reservoir.
The suction conduit of the second pump communicates with the accumulator reservoir and the second pump discharge communicates with a fine particle filter for pumping the coarse filtered coolant therethrough to produce a fine filtered and processed coolant which is returned through a discharge conduit communicating with the fine filter.
Each of the pumps is controlled by an electric switch connected to a float sensing the liquid levels within the accumulator reservoir, and the electric switches control pump operation to prevent overfilling of the accumulator reservoir or emptying thereof. The fine filter preferably employs an activated charcoal element capable of removing very small particles, as well as bacteria, from the coolant, and filter element spacing and support means within the fine filter permit the filter element to be readily replaced and serviced.
The fine filter also includes flow control means upstream of the filter element for controlling the direction of fluid flow to provide optimum filtering and prevent channeling through the filter element.
The components utilized in the system of the invention are economically manufacturable or commercially available, and the practice of the invention permits efficient coolant processing and reclaiming at relatively low cost made available to the small machine shop operator.